Kingspan

[pops92]

Single garage tiles and block stuff under it. I want to just put 50 or 100mm kingspan onto the apex beams to cover it. Is this a problem ?

 

[Cabinetman]

The recommendation on here from what I’ve read is to cut the King span 10 mil smaller all round, wedge it in place and then go around with expanding foam then take the wedges out when it’s set and fill in where the wedges were. Having just used some expanding foam for the first time in a while, it’s incredibly messy stuff and working upside down, I would hesitate to do what I have just described, if it was me I would measure top middle and bottom and cut as accurately as I could with a handsaw and push it into place, I’m sure I would soon get the knack of it so that it was nice and tight. Ian

 

[gregmcateer]

I think you need an air gap above the insulation, iirc

 

[Noel]

50mm usually.

 

[The Bear]

If it were me I wouldn’t try and fit it between the rafters in this situation. Would be incredibly frustrating to try and get it to fit and awkward to do. I’d fasten it underneath the rafters which would also be thermally more efficient

mark

 

[pops92]

If it were me I wouldn’t try and fit it between the rafters in this situation. Would be incredibly frustrating to try and get it to fit and awkward to do. I’d fasten it underneath the rafters which would also be thermally more efficient

mark

Now what you have just mentioned is what I was looking at doing. As losing 50 or 100mm will not cause a prolem to me. I can just nail to the beams seems the way to go.

 

[Phil Pascoe]

If you do seal it with expanding foam get yourself a couple of metres of pvc piping that'll fit the nozzle - you can use the can upside down easily with a couple of feet of pipe on it.

 

[Doug B]

Now what you have just mentioned is what I was looking at doing. As losing 50 or 100mm will not cause a prolem to me. I can just nail to the beams seems the way to go.

If you’re not over boarding the insulation I would make some washers from thin ply, hardboard etc to spread the load as the nail head will probably just pull straight through the insulation, when I’ve done this before I’ve screwed through the wooden washers as it’s less likely to damage the insulation.

 

[Sandyn]

When I was fitting it, I cut to size, at a very slight angle (to create a wedge fit) then fitted. Most times it was a tight fit, if it was very tight at any place, I would just take handsaw jammed between the wood and the Kingspan to take a very thin slice off. I used a baton and hammer to squeeze it in. It was messy but worked very well. To remove a small amount over a long length I used a concrete floor as abrasive. It is very easy to rub a mm or so off it. I just got good at it. Another of my totally useless skills!
I personally wouldn't use foam, too much hassle, too messy, too expensive and I would have had to trim all the extra foam for a flush fit. If nailing, you will need some kind of washer.

What about sticking to the rafters with grab adhesive?

 

[Jake]

Doing some of this in my attic. The Bahco insulation saw is worth every penny and more (it's like a very sharp knife rather than toothed, so much less mess). It's supposed to struggle with thicker foam according to some reviews but is absolutely great with the 75mm phenolic I'm using. Mine is mostly under rafters, some between studs, but new stub walls so regular - no problems sizing those for a tight friction fit.

 

[The Bear]

Buy a bag of these rather than make your own to hold it in place, i prefer screws to nails.
https://www.ebay.co.uk/itm/Tile-Bac...141107?hash=item2f1c5a45f3:g:yawAAOSwL7VWjhLyNormal cheap hard point saw to cut.
If you are not over boarding I would also tape the joints with aluminium tape from tololstation or screwfix

Mark

 

[pops92]

When I was fitting it, I cut to size, at a very slight angle (to create a wedge fit) then fitted. Most times it was a tight fit, if it was very tight at any place, I would just take handsaw jammed between the wood and the Kingspan to take a very thin slice off. I used a baton and hammer to squeeze it in. It was messy but worked very well. To remove a small amount over a long length I used a concrete floor as abrasive. It is very easy to rub a mm or so off it. I just got good at it. Another of my totally useless skills!
I personally wouldn't use foam, too much hassle, too messy, too expensive and I would have had to trim all the extra foam for a flush fit. If nailing, you will need some kind of washer.

What about sticking to the rafters with grab adhesive?

Hate the foam wont be using that.